In downhole oil and gas operations downhole equipment, such as downhole valves, sleeves, ICDs, packers, slips, toe sleeves and the like may be operated by use of pressure. For example, some equipment may be operated by use of hydrostatic pressure within the wellbore. In some cases equipment may be actuated by use of pressure differentials, for example between internal tubing pressure and external annulus pressures.
It is often the case in downhole operations that a defined sequence of events is required. However, if each event is pressure initiated, then there is a risk of the sequence being upset by a premature reaction of one event or device to a pressure meant for operation of a different event or device. For example, pressure testing is often required in downhole operations, such as to confirm the pressure integrity of completion strings following and/or during deployment. However, should the completion include one or more pressure activated devices then there is a risk that such devices are inadvertently actuated during pressure testing.